Radiations Role in Accelerating Galactic Outflow 2019 Athena++ User - PowerPoint PPT Presentation

Radiation’s Role in Accelerating Galactic Outflow � 2019 Athena++ User Meeting | Xiaoshan Huang � ( Shane W. Davis, Dong Zhang) �

� Radiation’s Role in Accelerating Galactic Outflow � • Galactic Outflow : Importance in Galaxy Evolution • Galaxy properties: galaxy luminosity function • Enrichment of IGM • S tar formation feedback

� Radiation’s Role in Accelerating Galactic Outflow � • Galactic Outflow : Observed Properties NGC253 � OH doublet � ( Spilker et al 2018) � ( Walter et al 2017) � • Velocity: • Cold gas: Molecular temperature �

� � Radiation’s Role in Accelerating Galactic Outflow � • Galactic Outflow : Driving Mechanism. Simulation Study - Schematic Picture - Entrainment in hot wind - (Scannapieco 2015) �

Radiation’s Role in Accelerating Galactic Outflow � • Galactic Outflow : Driving Mechanism. Simulation Study - Entrainment in hot wind - IR Radiation from SF regions - E - IR - C - A - Magn - B - UV (Scannapieco 2015) � (Zhang et al 2018) � surviving time: when cloud lose half of its initial mass �

Athena++ RHD code � • Directly Solve the multi-band RT Equation � • Couple with Hydrodynamic Equation � • Reduced Speed of Light Approximation �

Radiation’s Role in Accelerating Galactic Outflow � Fiducial Run � • Set-up � outflow � UV flux � outflow � close to starburst region � outflow � - Passive Scalar to track dust - Cloud - following Frame - Initial random perturbation on density - Uniform incoming radiation flux

Radiation’s Role in Accelerating Galactic Outflow � Density � Compression by radiation pressure è volume minimum è Re-expand by gas pressure �

Radiation’s Role in Accelerating Galactic Outflow � passive scalar: dust fraction • Cloud surviving time: � of cell � x direction � Radiation Flux �

Radiation’s Role in Accelerating Galactic Outflow � IR radiation � A very favorable acceleration condition � UV radiation � surviving time: UV radiation << IR radiation �

Radiation’s Role in Accelerating Galactic Outflow � • Take-away - Cold cloud being accelerated by UV radiation has significant shorter surviving time compared to IR radiation • Future Work: - Background condition? - What fraction of UV radiation in a mixing flux will destroy the cloud? - Cosmic Rays?

Radiation’s Role in Accelerating Galactic Outflow � • Dust escape from boundary? � solid: � dashed: �

Dust sublimation happens when mixing with background � dust temperature (only showed region with dust) � T/T 0 � dusty density distribution v.s. hot dust density � cloud mass evolution �

Radiation’s Role in Accelerating Galactic Outflow � • Optical depth � IR radiation � UV radiation �

Radiation’s Role in Accelerating Galactic Outflow � • Resolution �

Radiation’s Role in Accelerating Galactic Outflow � • Dimension

Radiation’s Role in Accelerating Galactic Outflow � Fiducial Run � • Set-up � outflow � UV flux � outflow � close to starburst region � outflow � - Passive Scalar field to track dust - Cloud - following Frame - Initial random perturbation on density - Uniform incoming radiation flux

Radiation’s Role in Accelerating Galactic Outflow � A very favorable IR radiation � acceleration condition � UV radiation � , Shane W. Davis) � 0.1Myr � IR radiation � Hot Wind � 0.1Myr � surviving time: UV radiation << IR radiation � (Zhang et al 2018) �

� � Radiation’s Role in Accelerating Galactic Outflow � • Galactic Outflow : Driving Mechanism. Simulation Study - Entrainment in hot wind - IR Radiation from SF regions - (Scannapieco 2015) � (Zhang et al 2018) � surviving time: when cloud lose half of its initial mass � -